HVAC units generally provide both conditioned and non-conditioned air to various locations via paths or airways. In general, these paths or airways are guided by ducts or other such structural means to ensure that the air coming from the HVAC unit reaches the proper destination and with the desired air temperature.
In the automotive context, for example, air from the HVAC is often conducted to various regions, both inside and outside of the vehicle. Conditioned air or non-conditioned and conditioned air mixed together, often exits or is ‘outletted’ or discharged to various areas of the vehicle to provide for passenger comfort. To achieve such comfort, air that passes through the HVAC unit arrives, with the help of air directing and/or air controlling devices, (such as valves, flaps, doors or other such air directing and controlling devices.), into outlets and, eventually paths that lead out of the HVAC unit.
There is, therefore, a need to have means to control the air directing and/or air controlling devices, such as, for example, valves, flaps, doors or other such similar air directing and/or controlling devices, to ensure that air reaches its destination in the proper volumes, and the proper speeds, and/or at the proper temperatures. In automotive HVAC units, it is often necessary to control air flows to more than one outlet from the unit. In fact, the desired control of air flows to multiple outlets via multiple air paths is often difficult to obtain, since to control air flow to multiple outlet paths, multiple air valves, flaps or other such air directing and controlling devices, is needed. For example, in the prior art, in HVAC units with three possible outlet paths, it is common to use two or more air valves. Each valve is motion controlled via an actuation source. The actuation source may be electric actuator motors, pneumatic actuation device, or a mechanical connection to the user control knob or lever (collectively referred to herein as actuator devices).
In addition, it is required that there be a means of transferring the mechanical motion from the actuation source to the air valve. This has generally be achieved by mechanical links, levers, gears or cams, or direct mechanical connection to the actuation device, (motion transferors) such solutions requiring a separate actuation device for each air valve. Alternatively, proper air flows and/or air characteristics may be found by reducing the quantity of air valves, thereby reducing the complexity of controlling the motion of each air valve, reducing the cost and increasing reliability.
With the current state of the art, multiple actuation devices are used for multiple air directing and/or air controlling devices, therefore providing for HVAC systems either with additional parts consisting of mechanical links, levers, gears or cams, or with additional parts particularly required for the use of the multiple actuation devices. These extra parts not only add cost, but may also reduce the reliability of the system. In addition, when mechanical links, levers, gears or cams are utilized, positional accuracy of the air valve, for example, with respect to the actuation device, is degraded, resulting in less control directing air flow to the desired outlet or of the temperature of the outlet air and increased potential for quality problems such as binding, noise, and incorrect airflow. The mechanical component such as links, levers, gears or cams require a high level of geometric accuracy and cam bind, disengage, or causes noises such as squeaks and rattles and thumps if not dimensioned correctly.